In vitro binding of 67Ga to isolated rat liver cells

In order to understand the mechanism of the accumulation of gallium citrate (Ga-67) in normal liver, an in vitro investigation system was developed using isolated rat liver cells, and various basal factors relating to 67Ga binding to normal rat liver cells were studied. In this study, the values of 67Ga binding to the liver cells increased in parallel with the number of cells; however, binding was hardly affected by higher doses of 67Ga. The binding of 67Ga to the cells was inhibited by the presence of ethylenediaminetetraacetate (EDTA) and citrate. Phosphate and bicarbonate (10(-2) M) slightly inhibited 67Ga binding to the cells. The binding of 67Ga to the cells increased as the pH was decreased. These results suggest that 67Ga binding to normal rat liver cells may occur in 'free' gallium. Moreover, the utilization of isolated rat liver cells is useful for understanding the 67Ga accumulation mechanism in normal liver.     

Site-specific conjugation of HIV-1 tat peptides to IgG: a potential route to construct radioimmunoconjugates for targeting intracellular and nuclear epitopes in cancer

Purpose Our objective was to study the cellular and nuclear uptake of ¹²³I-mouse IgG (¹²³I-mIgG) linked to peptides [GRKKRRQRRRPPQGYGC] harbouring the membrane-translocating and nuclear import sequences of HIV-1 tat protein.Methods Carbohydrates on mIgG were oxidized by NaIO₄, then reacted with a 40-fold excess of peptides. Displacement of binding of anti-mouse IgG (Fab specific; -mFab) to ¹²³I-mIgG by tat-mIgG or mIgG was compared. Internalization and nuclear translocation of ¹²³I-tat-mIgG in MDA-MB-468, MDA-MB-231 or MCF-7 breast cancer cells were measured. The immunoreactivity of imported tat-mIgG was evaluated by measuring binding of ¹²³I--mFab to cell lysate and by displacement of binding of ¹²³I-mIgG to -mFab by cell lysate. Biodistribution and nuclear uptake of ¹²³I-tat-mIgG, ¹²³I-mIgG and ¹²³I-tat were compared in mice bearing s.c. MDA-MB-468 tumours.Results There was a 15-fold decrease in affinity of -mFab for tat-mIgG compared with mIgG. Internalized radioactivity imported into the nucleus for ¹²³I-tat-mIgG in MDA-MB-468, MDA-MB-231 and MCF-7 cells was 61.5±0.6%, 60.3±3.6% and 64.7±1.0%, respectively. The binding of ¹²³I--mFab to lysate from MDA-MB-468 cells importing tat-mIgG was 17-fold higher than that for cells not exposed to tat-mIgG. Imported tat-mIgG competed with tat-mIgG for displacement of binding of ¹²³I-mIgG to -mFab. Conjugation of mIgG to tat peptides did not change tissue distribution. Nuclear localization for ¹²³I-tat-mIgG in MDA-MB-468 tumours was 28.1±5.6%, and for liver, spleen and kidneys it was 41.7±2.7%, 13.8±0.8% and 36.9±3.3%, respectively.Conclusion ¹²³I-tat-mIgG radioimunoconjugates suggest a route to the design of radiopharmaceuticals exploiting intracellular and nuclear epitopes.     

The mechanism of the localization of 67Gallium citrate in experimental abscesses

⁶⁷Ga accumulation in turpentine-induced abscesses, from 5 h to 20 days old, in the rat has been investigated, and the results indicate that this is dependent on polymorphonuclear leukocyte (PMN) infiltration of the inflamed site. ⁶⁷Ga concentration 24 h after injection correlates well with the activities of the lysosomal enzymes, aryl sulphatase and -glucuronidase, P0.001, and with the DNA content of the tissue. There is no direct relationship with the rate of DNA synthesis.The mechanism of lysosomal incorporation into PMNs is consistent with the factors involved in ⁶⁷Ga uptake into tumours and normal tissues.     

Fast diagnosis (6 h) of clinically silent pyonephrosis by combined use of 99mTc-MDP and 67Ga citrate

A fast diagnosis (6 h) of clinically latent pyonephrosis by combined use of ^99mTc-MDP and ⁶⁷Ga-citrate is reported. This technique combines the potential early detection of focal infectious processes by ⁶⁷Ga and the high-pulse separation possibility of multiple isotopes. A brief prospective study (6 months) showed the interest of this technique: in six cases focal bone and/or joint infections were found three of which were absolutely latent clinically.     

‘Hot’ and ‘cold’ lesions detected by gallium-67 scintigraphy in a pyogenic liver abscess

Most pyogenic liver abscesses appear to be not in a ⁶⁷Ga-citrate study; rarely, a warm or cold area may also be seen. We present a patient with a pyogenic liver abscess that had both cold and hot areas in the ⁶⁷Ga-citrate study. This striking finding is probably related to the different stages of evolution of the abscess.     

Scintigraphic evaluation of the liver in Fasciola hepatica with radiocolloid and 67Ga-citrate

A group of 23 patients with Fasciola hepatica have been studied in the province of Biscay. The diagnosis was reached after finding parasite eggs in the faeces or duodenal juice. The liver lesion was confirmed by means of macro and microscopic studies. Radiocolloid demonstrated the presence of cold areas in 18 patients; in 13 of them the uptake with ⁶⁷Ga was positive. These isotopic findings identified Fasciola hepatica as one of the causes of cold areas in traditional liver scans and positive ⁶⁷Ga uptake.     

Unexpected differences in early thyroidal trapping of iodide and pertechnetate

Compartmental analysis was applied to simultaneously acquired ¹³²I-iodide and ^99mTc-pertechnetate thyroid uptake data. The method allowed for arterio/venous differences in plasma tracer level and for an instantaneous phase of thyroid uptake.Observations in four thyrotoxic patients, before and during antithyroid drug therapy, revealed greater instantaneous uptake of TcO ₄ ^- . The results also revealed that instantaneous uptake of both I^– and TcO ₄ ^– may increase over the first six months of drug therapy. These findings could not be explained by the estimates of unidirectional clearance which were greater for I^- and varied little during the early stages of drug therapy.     

The role of lysosomal enzyme activity in the localization of 67gallium citrate

The distribution of ⁶⁷Ga citrate at 24 h post injection has been studied in the normal tissues of the mouse, rat and dog; 13 transplantable mouse tumours and 7 rat tumours have also been examined. The total activities of four lysosomal enzymes, aryl sulphatase, -glucuronidase, acid phosphatase and cathepsin-D were measured as well as the incorporation of thymidine-³H and leucine-¹⁴C as indicators of DNA and protein synthesis.The results show a close correlation between ⁶⁷Ga uptake and lysosomal enzyme activity in the tumours studied, which is an extension of the same relationship for normal tissues. It is suggested that the reported correlation between the uptake of ⁶⁷Ga and the rate of cellular proliferation is secondary to the primary function of the lysosome in the localisation of the nuclide, lysosomal enzyme activity also being enhanced in situations of increased metabolic activity. A similar relationship appears to occur following administration of ¹¹¹In-Bleomycin and ^99mTc-Citrate.Some of the data was presented at the 2nd Congress of the European Society of Nuclear Medicine, London, April, 1978     

Enhancement of [123I]β-CIT binding in the striatum with clomipramine: Is there a serotonin-dopamine interaction?

Many reports support the concept of serotonergic-dopaminergic interaction in the brain. However, at present, there are few methods to study this relationship in vivo. The purpose of this study was to investigate the effect of serotonin (5-HT) uptake inhibitor, clomipramine, on a dopamine (DA) transporter ligand, [¹²³I]-CIT (RTI-55), in rat brain. Dose-dependent changes in [¹²³I]-CIT specific binding induced by clomipramine were studied in the striatum (rich in DA transporter) and the hypothalamus (rich in 5-HT transporter). The changes in the time-activity curves of [¹²³I]-CIT specific binding after clomipramine injection were also examined in these two regions. Using the cerebellum as the reference region,k ₃ andk ₄ values with and without clomipramine administration were estimated by a two-compartment kinetic analysis. Clomipramine inhibited [¹²³I]-CIT specific binding in the hypothalamus, but enhanced its specific binding in the striatum in a dose-dependent manner. Kinetic analysis showed thatk ₃ in the striatum was increased by 55%. In conclusion, enhancement of [¹²³I]-CIT binding in the striatum after clomipramine administration indicated the possibility of 5-HT-DA interaction.     

Absolute quantitation of gallium-67 citrate accumulation in the lungs and its importance for the evaluation of disease activity in pulmonary sarcoidosis

Our modification of a method for the absolute quantification of gallium-67 uptake in lungs with a scintillation camera and computer is described. The uptake of ⁶⁷Ga in lungs, expressed in percentage of administered radioactivity, was determined by the transmission-emission method. We proved theoretically and experimentally that a ⁶⁷Ga planar source could be replaced with a ⁵⁷Co planar source. The performance of lung perfusion scans allows a more accurate delineation of the regions of interest on gallium scans. The method was applied to control subjects (n=27) and to patients (n=114) suffering from biopsy-proven pulmonary sarcoidosis (28 with inactive and 86 with active disease). The obtained results were compared with chest X-ray findings, the percentage of lymphocytes in the bronchoalveolar fluid (BAF-ly%), and serum angiotensin-converting enzyme (SACE) values. The method seems suitable for the assessment of disease activity in sarcoidosis. It is more accurate in detecting parenchymal involvement in lung sarcoidosis than the commonly used X-ray criteria. No correlation was found between ⁶⁷Ga uptake and the BAF-ly% and SACE values. Correspondence to: M. Mysliveek     

Biological behavior of 67Ga-citrate in New Zealand White rabbits

The pharmacokinetics, protein binding, excretion and tissue distribution of ⁶⁷Ga after the administration of ⁶⁷Ga-citrate to New Zealand White rabbits is described. Data for ⁶⁷Ga blood levels were best described by an equation with three exponential components exhibiting half lives of 0.25 h, 7.4 h and 19.5 h, with almost all of the activity in a protein bound form. Weekly urinary excretion ( 27%), possibly in a metabolized form, and fecal elimination (20%) were greater than the reported values in man, but there was a similar organ distribution pattern in these animals as in man. The overall biological handling was judged to be similar in both species making the rabbit a suitable model for further ⁶⁷Ga-citrate studies in vivo.     

The role of ferritin in the intracellular distribution of gallium 67

The binding of gallium 67 or iron 59 to ferritin in vitro was investigated using equilibrium dialysis. Gallium 67 did not bind to apo-ferritin until the protein was transformed into ferritin in the presence of iron citrate. Apotransferrin inhibited the binding of ⁶⁷Ga to ferritin, especially in the presence of sodium bicarbonate and citrate, thus indicating that ⁶⁷Ga has not gained access to ferritin from its complex with transferrin. Similar inhibition was observed for ferritin-⁵⁹Fe. The release of ⁵⁹Fe from its transferrin complex was enhanced by ATP, citrate, or ascorbic acid, while these reagents did not stimulate the dissociation of ⁶⁷Ga from its transferrin complex. On the other hand, ⁶⁷Ga injected intravenously in vivo was not found in the ferritin fractions of rat liver, kidney, and tumor. The difference between experimental results in vivo and in vitro supports the hypothesis that ⁶⁷Ga in the cytoplasm is not labile enough to be bound to ferritin. We have indicated a significant role of ferritin in distinguishing between ⁶⁷Ga and ⁵⁹Fe in the cell, and provided some clues to interpret the chemical forms of ⁶⁷Ga in the cytoplasm.     

Detection of bone marrow and extramedullary involvement in patients with non-Hodgkin’s lymphoma by whole-body MRI: comparison with bone and <Superscript>67</Superscript>Ga scintigraphies

The aim of this study was to evaluate the diagnostic potential of whole-body MRI (WB-MRI) for the detection of bone marrow and extramedullary involvement in patients with non-Hodgkins lymphoma. WB-MRI, which was performed on 34 patients, consisted of the recording of T1-weighted spin-echo images and a fast STIR sequence covering the entire skeleton. The WB-MRI findings for bone marrow and extramedullary involvement were compared with those from ⁶⁷Ga and bone scintigraphies and bone marrow biopsy results. Two MRI specialists reviewed the WB-MRI results and two expert radiologists in the field of nuclear medicine reviewed the bone and ⁶⁷Ga scintigraphy findings. Bone marrow and extramedullary involvement of non-Hodgkins lymphoma were confirmed by follow-up radiographs and CT and/or a histological biopsy. The detection rate of WB-MRI was high. More bone marrow involvement was detected by biopsy, and more lesions were detected by scintigraphies. In total, 89 lesions were detected by WB-MRI, whereas 15 were found by biopsy, 5 by ⁶⁷Ga scintigraphy, and 14 by bone scintigraphy. WB-MRI could also detect more extramedullary lesions than ⁶⁷Ga scintigraphy; i.e., 72 lesions were detected by WB-MRI, whereas 54 were discovered by ⁶⁷Ga scintigraphy. WB-MRI is useful for evaluating the involvement of bone marrow and extramedullary lesions throughout the skeleton in patients with non-Hodgkins lymphoma.     

Methamphetamin—ein Metabolit der Appetitzügler Benzphetamin und Furfenorex

Zusammenfassung Die Appetitzügler Didrex (1) [1-Phenyl-2-(N, N-methyl-benzyl-amino)propan — Benzphetamin] und Frugalan (2) [1-Phenyl-2-(N, N-methyl-furfuryl-amino)propan = Furfenorex] werden — wie GC-MS-Analysen ergaben — beim Menschen zu Methamphetamin (3) (1-Phenyl-2-methylamino-propan) metabolisiert. Käufliche Muster beider Präparate enthielten neben anderen Verunreinigungen Spuren von Methamphetamin (3).

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Summary The anorectics Didrex (1) [1-Phenyl-2-(N, N-methyl-benzyl-amino)propane = Benzphetamine] and Frugalan (2) [1-Phenyl-2-(N, N-methyl-furfuryl-amino)propane = Furfenorex] are metabolized to methamphetamine (3) (1-Phenyl-2-methylamino-propane) in man as demonstrated by GC-MS-analysis. Commercially available samples of the two drugs contained — besides other impurities — traces of methamphetamine (3).

Institut für Rechtsmedizin der Universität Göttingen.     

Relation between 67Ga uptake and iron metabolism in rat tissues

The relationship between ⁶⁷Ga uptake and iron metabolism was investigated in rat tissues. ⁶⁷Ga and ⁵⁹Fe(II) both accumulated in the mitochondrial-lysosomal fraction after being injected. Moreover, they both showed especially high affinity for heparan sulfate (HS) among various acid mucopolysaccharides (AMPS). When iron (ferrous citrate) was injected IV before, simultaneously with, and after ⁶⁷Ga citrate IV injection, ⁶⁷Ga uptake was significantly inhibited in normal rat liver in all cases. Elevated ⁶⁷Ga uptake in the liver of CCl₄-treated rats was also lowered to the control level by iron pretreatment. High zinc intake remarkably elevated the ⁶⁷Ga uptake in rat liver. The contents of iron in the liver and liver AMPS of 0.75% zinc-fed rats were lowered in comparison with those in controls. Thus, the elevation of ⁶⁷Ga uptake in the liver of zinc-fed rats might be due to the decreased of iron bound to HS.     

Positive 131Cesium scanning in parathyroid adenoma

In a case of primary hyperparathyroidism, a palpable nodule, at the base of the right lobe of the thyroid, proved cool during ^99mTc scanning, but hot when scanned with radiocesium. The uptake of this tracer was higher than the uptake of ⁷⁵Se-selenomethionine after suppression with T₃.The authors discuss the possibility of cases of false-positive radiocesium uptake in extrathyroid nodules, and in particular, the use of this tracer for the detection of parathyroid adenoma by scanning.     

Proportional anatomical stereotactic atlas for visual interpretation of brain SPET perfusion images

A semi-automatic method was developed to determine the anterior (AC) and posterior (PC) commissures on brain single-photon emission tomographic (SPET) perfusion images, and then to draw the proportional anatomical Talairach's grid on each axial SPET image. First, the AC-PC line was defined on SPET images from the linear regression of four internal landmarks (frontal pole of the brain, inferior limit of the anterior corpus callosum, sub-thalamic point and occipital pole). Second, the SPET position of AC and PC points on the AC-PC line was automatically determined from measurements made on hard copies of magnetic resonance (MR) images of the patients. Finally, a proportional Talairach's grid was automatically drawn on each axial SPET image. To assess the accuracy of localization of AC and PC points, co-registered technetium-99m hexamethylpropylene amine oxime SPET and MR images from 11 subjects were used. The mean displacements between estimated points on SPET and true points on MRI (x=sagittal, y=frontal and z=axial displacement) were calculated. The mean displacements (in mm) were x=–1.4±1.8, y=–1.7±3.3 and z=–1.1±2.5 for AC, and x=–1.8±1.8, y=0.3±3.2 and =–1.3±2.7 for PC. These displacements represented an error of less than 5 mm at the anterior or posterior pole of the brain or at the vertex. Intra- and inter-observer comparisons did not reveal significant differences in mean displacements. Thus, this semi-automatic method results in reproducible and accurate stereotactic localization of SPET perfusion abnormalities. This method can be used routinely for repeat follow-up studies in the same subject as well as in different individuals without requiring SPET MRI co-registration.     

Untersuchungen zum dünnschichtchromatographischen Nachweis eines neuartigen Tranquilizers aus der Trioxazin-Reihe (Versuchspräparat Nr. 518 der Firma Knoll AG.)

Summary The tranquilizer-substance Trioxazine is described and investigations were made for detecting the substance and its metabolites in the urine after intake. It was found, that the unchanged tranquilizer as well as 3 metabolites were excreted. The substance could easily be extracted out of urine with chloroforme after acidifying with hydro-chloric acid. The extract was separated on silica-gel GF₂₅₄-thinlayer-plate in the solvent CHCl₃-n-Heptan-Ethanol (111). For the detection of the substances on the plate it was found, that spraying them with a modified reagent ofSonnenschein, consisting of Cer(IV)sulphate, trichloraceticacid and conc. sulfuric. acid give red spots. An amount of 5 g of Trioxazine can thus be detected. Trioxazine also reacts with conc. nitric acid to a deep red colour.

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Vorgetragen auf der Tagung der Deutschen Gesellschaft für Gerichtliche und Soziale Medizin in Freiburg i. Br. im Oktober 1966.     

A new method for labeling microspheres with 68Ga

We have developed a simple, highly efficient, and rapid technique for labeling a commercially available human serum albumin microsphere preparation with ⁶⁸Ga for use in positron tomography. An isotonic acetate buffer system is used. Maximum ⁶⁸Ga labeling is obtained at pH 4.8 (97%) but deviations from that pH (e.g., 0.5 of a pH unit) produce only minor decreases in binding efficiency. The preparation is stable on standing over a period of 4 h, and in vivo studies in the rat and dog show it to be specific for the lungs. Little change occurs in the tissue distribution of ⁶⁸Ga over a period of approximately 1 h.     

Evaluation of one dimensional profile scans with a whole body counter -82bromide space in liver cirrhosis: Concise communication

One dimensional profile scans with a whole body counter are refocused with a linear space invariant filter in the frequency domain, Hanning window and inverse system transfer function. Artifacts are climinated in a way that a clinically applicable method is developed. Topographic information is achieved with the highly energetic nuclide⁸²bromide. The bromide space (extracellular volume) in patients with liver cirrhosis (n=9) compared to normal subjects (n=10) is increased most in the upper abdominal thoracic region.This paper is part of medical doctorate of O. Schober